ESIN

In Monteggia lesions, reduction and stable fixation of the ulna are required to ensure stable reduction of the radial head. The most important factor is restoration of the length of the ulna.

The radial head usually spontaneously reduces once the ulna is out to length.

If, after assessment of the fixation, the radial head is not accurately centered to the center of the capitellum in AP and lateral views, consider overcorrection of the ulna (see illustration).

The usual strategy to deal with a Monteggia lesion is:

1. Stable anatomical reduction or overcorrection of the ulna
2. Assess the radial head position and stability using image intensification.
3. If necessary, revise the position of the ulna.
4. If necessary, perform an open reduction of the radial head.

This procedure is normally performed with the patient in a supine position.

The alignment of the ulna is addressed first.

The ulna must be fully out to length and stable to prevent redislocation or subluxation of the radial head.

The steps for ulnar fracture fixation are described in the ESIN procedure (retrograde nail insertion) for each fracture type:

• ESIN for bowing
• ESIN for greenstick fracture
• ESIN for complete fracture

The radial head will usually reduce closed and remain stable once the ulna has been aligned.

Rotational movements of the forearm may be necessary to complete the reduction of the radial head.

After fixation of the ulna, use an image intensifier to carefully evaluate the position of the radial head relative to the capitellum.

This must be confirmed through a full range of flexion, extension, pronation and supination.

An arthrogram may be helpful, particularly in younger children with an unossified proximal radius.

At this stage the ulnar reduction can be revised if required, often to an overcorrected position, which usually results in a stable and anatomic reduction of the radial head.

This can be achieved by overbending and reinserting the ulnar nail. An external fixator or a plate can produce further overcorrection if needed.

There is a strong tendency for the radial head to redislocate in a Monteggia fracture with plastic deformity of the ulna.

This is due to rebound of the ulna. Correction of the ulnar deformity with a precontoured elastic nail is recommended. If this is not successful, an osteotomy of the ulna should be considered.

Both of these maneuvers should be performed before considering open reduction of the radial head.

Complete reduction with the nail may not be possible in the following cases:

• Severe bowing
• Bowing unresponsive to intraoperative correction
• Narrow nail in a small medullary canal

In this situation, a small osteotome can be used to divide the bone through a small incision over the apex of the bowing.

If there is residual subluxation or instability in any position after optimization of the ulnar correction, there may be interposed tissue (usually annular ligament) in the radiocapitellar joint and an open reduction should be performed.

Perform a lateral approach and manually reduce the radial head.

The annular ligament is the most common intraarticular block to reduction. In rare cases the ligament can be gently repositioned around the radial head.

More often the ligament must be incised or excised to allow reduction of the radial head.

Reassess the position and stability of the radial head by direct visual inspection and image intensification.

Check the completed osteosynthesis with image intensification. These images should be retained for documentation or alternatively an x-ray should be obtained before discharge.

Make sure that the desired reduction has been achieved, the nail is of appropriate length and the radial head remains in the appropriate position.

Whilst the child remains in bed, the forearm should be elevated on pillows to reduce swelling and pain.

They should be encouraged to use the arm.

Cast immobilization is not necessary and hinders early recovery of joint movement.

For Monteggia lesions treated with ulnar nailing, the forearm may be immobilized in a cast in the position of maximum stability of the radiocapitellar joint for 2-4 weeks.

Ibuprofen and paracetamol should be administered regularly during the first 4-5 days of injury, with additional oral narcotic medication for breakthrough pain.

If pain is increasing the child should be examined.

The child should be examined regularly, to ensure finger range of motion is comfortable and adequate.

Neurological and vascular examination should also be performed.

Compartment syndrome should be considered in the presence of increasing pain, especially pain on passive stretching of muscles, decreasing range of active finger motion or deteriorating neurovascular signs, which are a late phenomenon.

See also the additional material on postoperative infection.

Compartment syndrome is a possible early postoperative complication that may be difficult to diagnose in younger children.

The presence of full passive or active finger extension, without discomfort, excludes muscle compartment ischemia.

If there are signs of a compartment syndrome:

1. If the child is in a cast, split the cast, along its full length down to skin level.
2. Elevate the limb.
3. Encourage active finger movement.
4. Reexamine the child after 30 min.

If a definitive diagnosis of compartment syndrome is made, then a fasciotomy should be performed without delay.

Discharge from hospital follows local practice and is usually possible after 1-3 days.

The parent/carer should be taught how to assess the limb.

They should also be advised to return if there is increased pain or decreased range of finger movement.

It is important to provide parents with the following additional information:

• The warning signs of compartment syndrome, circulatory problems and neurological deterioration
• Hospital telephone number
• Information brochure

For the first few days, the elbow and forearm can be elevated on a pillow, until swelling decreases and comfort returns.

The arm can be placed in a sling for a few days until the patient is pain free. Many children are more comfortable without support.

Early movement of the forearm should be encouraged as soon as the patient is pain free.

Physiotherapy is normally not indicated.

The first clinical and radiological follow-up depends on the age of the child and is usually undertaken 4-6 weeks postoperatively.

At this point, the child should be able to move the forearm almost fully with some limited rotation caused by callus formation.

AP and lateral x-rays are required.

See also the additional material on healing times.

Nail removal is delayed until the fracture has modelled completely and can be performed as a day case, under general anesthesia.

The nail end in the proximal ulna can often be easily palpated.

In the distal ulna, the nail end may slip under tendons and nerves. This may irritate the soft tissues and make it difficult to palpate the nail tip.

Exposure of the nail end should be performed under direct vision with small retractors.

In most cases, a small bursa has formed. Once this bursa is opened, the end of the nail can be seen.

The nail can be removed with the extraction pliers, or a similar clamp. A strong needle holder is also useful.